1. Filed of the Invention
The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus having a structure for removing developer left on an image supporting member therefrom with a blade.
2. Description of Related Art
In an electrophotographic image forming apparatus, a toner image is formed on a photoreceptor surface, which serves as an image supporting member. The toner image is transferred from the photoreceptor surface to a transfer member such as an intermediate transfer belt or the like. Developer, which contains toner, left on the photoreceptor surface after the image transfer, is removed therefrom with a blade arranged to contact with the photoreceptor surface.
In this regard, while the developer left on the photoreceptor surface after the image transfer is removed with the blade, the developer serves as a lubricant between the photoreceptor surface and the blade. Therefore, there is a possibility that a shortage of developer on the photoreceptor surface would cause curling of the blade. Image forming apparatuses taking measures to avoid this trouble are known. For example, in an image forming apparatus disclosed in Japanese Patent Laid-Open Publication No. 2005-257787, a brush temporarily storing a part of developer left after image transfer is arranged immediately upstream from a blade in a rotating direction of the photoreceptor. In such a conventional image forming apparatus, when the image density that is the ratio of the square measure of an image area to the square measure of a print medium becomes low, that is, when the amount of developer supplied from a developing device to a photoreceptor surface decreases, the developer stored in the brush is released.
Incidentally, only a limited amount of developer can be stored in the brush. In the conventional image forming apparatus, therefore, in such cases as a case of forming low-density images continuously, a shortage of developer on the photoreceptor surface cannot be resolved by the release of developer from the brush, thereby causing trouble such as curling of the blade.